Terms of use

Last updated August 9, 2026.

By using Keen, you're agreeing to these terms. Please read them — they're kept as short and plain as we can make them.

What Keen is

Keen is a daily Sudoku puzzle habit. It is not a medical product, and it makes no claim to prevent, treat, or diagnose any cognitive condition. Any research we reference is about puzzle engagement in general, described only in correlational terms.

Your account

You're responsible for keeping access to your sign-in email secure. Let us know at hello@keensudoku.com if you believe your account has been accessed without your permission.

Subscriptions, trials, and billing

• Monthly and annual self-purchase plans start with a 7-day free trial and renew automatically at the price shown at checkout, unless you cancel first.
• You can cancel anytime from your account page; cancelling stops future charges but doesn't refund the current billing period.
• A gift purchase is a single, one-time charge — it never recurs and has nothing to cancel.
• All payments are processed by Stripe. We don't store your full card details.

Gifting Keen

A gift purchase creates a one-time redemption code tied to lifetime access. It's your responsibility to make sure the code reaches the person you intend to give it to — we can't reissue a code that's been redeemed by someone else.

Acceptable use

Please don't try to disrupt the service, access another person's account without permission, or use Keen for anything unlawful. We may suspend accounts that do.

Disclaimer and liability

Keen is provided “as is.” We work to keep it reliable, but we don't guarantee it will always be available or error-free. To the extent permitted by law, our liability to you is limited to the amount you've paid us in the 12 months before a claim.

Changes

We may update these terms as the product changes. If we make a material change, we'll post the update here with a new date.

Contact

Questions about these terms: hello@keensudoku.com.